U.S. patent application number 10/863142 was filed with the patent office on 2005-06-16 for method for treating a bifurcated vessel.
Invention is credited to Burgermeister, Robert S., Hojeibane, Hikmat, Krever, Matthew, Leon, Martin B., Majercak, David C., Park, Jin S..
Application Number | 20050131524 10/863142 |
Document ID | / |
Family ID | 46205250 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050131524 |
Kind Code |
A1 |
Majercak, David C. ; et
al. |
June 16, 2005 |
Method for treating a bifurcated vessel
Abstract
A method for treating a bifurcated vessel, wherein the
bifurcated vessel has a main vessel and a side branch vessel
extending from the main vessel. The method includes the steps of:
identifying a site in the main vessel and placing a stent at the
site in the main vessel. The stent includes a lattice defining a
substantially cylindrical configuration having a proximal end
portion and a distal end portion, and a middle portion between the
proximal end portion and the distal end portion. The lattice is
movable from a crimped state to an expanded state. The lattice has
a plurality of adjacent hoops. Each hoop has a plurality of
adjacent loops, a plurality of bridges connecting adjacent hoops,
and a plurality of extensions on at least some portions of the
lattice. Each of the hoops and bridges define a cell. The proximal
end portion and the distal end portion of the lattice have at least
one cell respectively and the middle portion of the lattice has at
least one cell. The at least one cell of the middle portion has
spacing between adjacent hoops that is greater than spacing between
adjacent hoops of the at least one cell of the proximal end portion
and the distal end portion respectively. The at least one cell of
the middle portion is dilated adjacent the side branch vessel and a
surface of the side branch vessel is supported with at least one of
the plurality of the extensions by deformably moving the at least
one of the plurality of extensions away from the lattice and into
contact with the surface of the side branch vessel.
Inventors: |
Majercak, David C.;
(Stewartsville, NJ) ; Krever, Matthew; (Warren,
NJ) ; Park, Jin S.; (Parsippany, NJ) ;
Burgermeister, Robert S.; (Bridgewater, NJ) ;
Hojeibane, Hikmat; (Princeton, NJ) ; Leon, Martin
B.; (New York, NY) |
Correspondence
Address: |
PHILIP S. JOHNSON
JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
46205250 |
Appl. No.: |
10/863142 |
Filed: |
June 8, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10863142 |
Jun 8, 2004 |
|
|
|
10373489 |
Feb 25, 2003 |
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Current U.S.
Class: |
623/1.15 |
Current CPC
Class: |
A61F 2/915 20130101;
A61F 2002/91558 20130101; A61F 2002/91541 20130101; A61F 2230/0054
20130101; A61F 2/91 20130101 |
Class at
Publication: |
623/001.15 |
International
Class: |
A61F 002/06 |
Claims
What is claimed is:
1. A method for treating a bifurcated vessel, the bifurcated vessel
having a main vessel and a side branch vessel extending from the
main vessel, the method comprising the steps of: identifying a site
in the main vessel; placing a stent at the site in the main vessel,
the stent comprising: a lattice defining a substantially
cylindrical configuration having a proximal end portion and a
distal end portion, and a middle portion between the proximal end
portion and the distal end portion, the lattice being movable from
a crimped state to an expanded state, the lattice having a
plurality of adjacent hoops; a plurality of bridges connecting
adjacent hoops; a plurality of extensions on the lattice; each of
the hoops and bridges defining a cell; and the proximal end portion
and the distal end portion of the lattice having at least one cell
respectively and the middle portion of the lattice having at least
one cell, the at least one cell of the middle portion having
spacing between adjacent hoops greater than spacing between
adjacent hoops of the at least one cell of the proximal end portion
and the distal end portion respectively; dilating the at least one
cell of the middle portion adjacent the side branch vessel; and
supporting a surface of the side branch vessel with at least one of
the plurality of the extensions by deformably moving the at least
one of the plurality of extensions away from the lattice and into
contact with the surface of the side branch vessel.
2. The method according to claim 1, further comprising dilating the
at least one cell of the middle portion adjacent the side branch
vessel with a balloon.
3. The method according to claim 1, further comprising dilating the
at least one cell of the middle portion adjacent an ostium of the
side branch vessel.
4. The method according to claim 3, further comprising dilating the
at least one cell of the middle portion adjacent an ostium of the
side branch vessel with a balloon.
5. The method according to claim 3, further comprising placing a
second stent in the side branch vessel.
6. The method according to claim 5, further comprising placing the
second stent in the side branch vessel at the ostium.
7. The method according to claim 6, further comprising placing the
second stent in the side branch vessel adjacent the dilated at
least one cell of the middle portion of the first stent.
8. The method according to claim 6, further comprising placing the
second stent in the side branch vessel within the dilated at least
one cell of the middle portion of the first stent.
9. A method for treating a bifurcated vessel, the bifurcated vessel
having a first vessel and a second vessel extending from the first
vessel, the method comprising the steps of: identifying a site in
the first vessel; placing a stent at the site in the main vessel,
the stent comprising: a lattice defining a substantially
cylindrical configuration having a proximal end portion and a
distal end portion, and a middle portion between the proximal end
portion and the distal end portion, the lattice being movable from
a crimped state to an expanded state, the lattice having a
plurality of adjacent hoops; a plurality of bridges connecting
adjacent hoops; a plurality of extensions on the lattice; each of
the hoops and bridges defining a cell; and the proximal end portion
and the distal end portion of the lattice having at least one cell
respectively and the middle portion of the lattice having at least
one cell, the at least one cell of the middle portion having
spacing between adjacent hoops greater than spacing between
adjacent hoops of the at least one cell of the proximal end portion
and the distal end portion respectively; dilating the at least one
cell of the middle portion adjacent the second vessel; and
supporting a surface of the second vessel with at least one of the
plurality of the extensions by deformably moving the at least one
of the plurality of extensions away from the lattice and into
contact with the surface of the second vessel.
10. The method according to claim 9, further comprising dilating
the at least one cell of the middle portion adjacent the second
vessel with a balloon.
11. The method according to claim 9, further comprising dilating
the at least one cell of the middle portion adjacent an ostium of
the second vessel.
12. The method according to claim 11, further comprising dilating
the at least one cell of the middle portion adjacent an ostium of
the second vessel with a balloon.
13. The method according to claim 11, further comprising placing a
second stent in the second vessel.
14. The method according to claim 13, further comprising placing
the second stent in the second vessel at the ostium.
15. The method according to claim 14, further comprising placing
the second stent in the second vessel adjacent the dilated at least
one cell of the middle portion of the first stent.
16. The method according to claim 14, further comprising placing
the second stent in the second vessel within the dilated at least
one cell of the middle portion of the first stent.
17. A method for treating a bifurcated vessel, the bifurcated
vessel having a main vessel and a side branch vessel extending from
the main vessel, the method comprising the steps of: identifying a
site in the main vessel; placing a stent at the site in the main
vessel, the stent comprising: a lattice defining a substantially
cylindrical configuration having a proximal end portion and a
distal end portion, and a middle portion between the proximal end
portion and the distal end portion, the lattice having a crimped
state and an expanded state, the lattice having a plurality of
adjacent hoops; a plurality of bridges connecting adjacent hoops; a
plurality of extensions on the lattice; each of the hoops and
bridges defining a cell; and the proximal end portion and the
distal end portion of the lattice having at least one cell
respectively and the middle portion of the lattice having at least
one cell, the at least one cell of the middle portion having
spacing between adjacent hoops greater than spacing between
adjacent hoops of the at least one cell of the proximal end portion
and the distal end portion respectively; expanding the stent and
the at least one cell of the middle portion adjacent the side
branch vessel; and supporting a surface of the side branch vessel
with at least one of the plurality of the extensions by deformably
moving the at least one of the plurality of extensions away from
the lattice and into contact with the surface of the side branch
vessel.
18. The method according to claim 17, further comprising expanding
the at least one cell of the middle portion adjacent the side
branch vessel based on shape memory properties of the at least one
cell of the middle portion of the stent.
19. The method according to claim 17, further comprising expanding
the at least one cell of the middle portion adjacent an ostium of
the side branch vessel.
20. The method according to claim 19, further comprising expanding
the at least one cell of the middle portion adjacent an ostium of
the side branch vessel based on shape memory properties of the at
least one cell of the middle portion of the stent.
21. The method according to claim 19, further comprising placing a
second stent in the side branch vessel.
22. The method according to claim 21, further comprising placing
the second stent in the side branch vessel at the ostium.
23. The method according to claim 22, further comprising placing
the second stent in the side branch vessel adjacent the expanded at
least one cell of the middle portion of the first stent.
24. The method according to claim 22, further comprising placing
the second stent in the side branch vessel within the expanded at
least one cell of the middle portion of the first stent.
25. A method for treating a bifurcated vessel, the bifurcated
vessel having a first vessel and a second vessel extending from the
first vessel, the method comprising the steps of: identifying a
site in the first vessel; placing a stent at the site in the main
vessel, the stent comprising: a lattice defining a substantially
cylindrical configuration having a proximal end portion and a
distal end portion, and a middle portion between the proximal end
portion and the distal end portion, the lattice being movable from
a crimped state to an expanded state, the lattice having a
plurality of adjacent hoops; a plurality of bridges connecting
adjacent hoops; a plurality of extensions on the lattice; each of
the hoops and bridges defining a cell; and the proximal end portion
and the distal end portion of the lattice having at least one cell
respectively and the middle portion of the lattice having at least
one cell, the at least one cell of the middle portion having
spacing between adjacent hoops greater than spacing between
adjacent hoops of the at least one cell of the proximal end portion
and the distal end portion respectively; expanding the stent and
the at least one cell of the middle portion adjacent the second
vessel; and supporting a surface of the second vessel with at least
one of the plurality of the extensions by deformably moving the at
least one of the plurality of extensions away from the lattice and
into contact with the surface of the second vessel.
26. The method according to claim 25, further comprising expanding
the at least one cell of the middle portion adjacent the second
vessel based on shape memory properties of the at least one cell of
the middle portion of the stent.
27. The method according to claim 25, further comprising expanding
the at least one cell of the middle portion adjacent an ostium of
the second vessel.
28. The method according to claim 27, further comprising dilating
the at least one cell of the middle portion adjacent an ostium of
the second vessel based on shape memory properties of the at least
one cell of the middle portion of the stent.
29. The method according to claim 27, further comprising placing a
second stent in the second vessel.
30. The method according to claim 29, further comprising placing
the second stent in the second vessel at the ostium.
31. The method according to claim 30, further comprising placing
the second stent in the second vessel adjacent the expanded at
least one cell of the middle portion of the first stent.
32. The method according to claim 30, further comprising placing
the second stent in the second vessel within the expanded at least
one cell of the middle portion of the first stent.
Description
FIELD OF THE INVENTION
[0001] This is a continuation-in-part application ofU.S. Ser. No.
10/373,489 filed Feb. 25, 2003 which is incorporated herein by
reference.
[0002] The present invention relates, in general, to intralumenal
medical devices, and, more particularly, to a new and useful stent
having a non-uniform longitudinal pattern whereby the center
section of the stent is more open in design than the proximal and
distal sections of the stent as well as deformable struts for
supporting and conforming to the ostium of a vessel side branch for
enhancing vessel coverage and accommodating the side branches of
vessels.
BACKGROUND ART
[0003] A stent is commonly used as a tubular structure left inside
the lumen of a duct to relieve an obstruction. Commonly, stents are
inserted into the lumen in a non-expanded form and are then
expanded autonomously (or with the aid of a second device) in situ.
When used in coronary artery procedures such as an angioplasty
procedure for relieving stenosis, stents are placed percutaneously
through the femoral artery. In this type of procedure, stents are
delivered on a catheter and are either self-expanding or, in the
majority of cases, expanded by a balloon. Self-expanding stents do
not need a balloon to be deployed. Rather the stents are
constructed using metals with spring-like or superelastic
properties (i.e., Nitinol), which inherently exhibit constant
radial support. Self-expanding stents are also often used in
vessels close to the skin (i.e., carotid arteries) or vessels that
can experience a lot of movement (i.e., popliteal artery). Due to a
natural elastic recoil, self-expanding stents withstand pressure or
shifting and maintain their shape.
[0004] As mentioned above, the typical method of expansion for
balloon expanded stents occurs through the use of a catheter
mounted angioplasty balloon, which is inflated within the stenosed
vessel or body passageway, in order to shear and disrupt the
obstructions associated with the wall components of the vessel and
to obtain an enlarged lumen.
[0005] Balloon-expandable stents involve crimping the device onto
an angioplasty balloon. The stent takes shape as the balloon is
inflated and remains in place when the balloon and delivery system
are deflated and removed.
[0006] In addition, balloon-expandable stents are available either
pre-mounted or unmounted. A pre-mounted system has the stent
already crimped on a balloon, while an unmounted system gives the
physician the option as to what combination of devices (catheters
and stents) to use. Accordingly, for these types of procedures, the
stent is first introduced into the blood vessel on a balloon
catheter. Then, the balloon is inflated causing the stent to expand
and press against the vessel wall. After expanding the stent, the
balloon is deflated and withdrawn from the vessel together with the
catheter. Once the balloon is withdrawn, the stent stays in place
permanently, holding the vessel open and improving the flow of
blood.
[0007] Additionally, the presence of vessel side branches has had a
major influence on the strategy of angioplasty for over a decade.
It is common thought that over half of angioplasty procedures may
place a vessel side branch in danger. The presence of side branches
may also increase procedural complications. The occlusion rate of
side branches during coronary angioplasty ranges from 3-15%,
depending on the clinical and anatomic features of the vessels.
Stents may improve or worsen the flow through vessel side branches
in both elective and bailout settings. The concept of "stent jail"
is described as the incarceration of vessel side branches when
their ostia are covered and made inaccessible by trunk vessel
stenting.
[0008] To date, there have been no adequate stent designs or
methods for stenting a bifurcated vessel that can avoid the problem
of stent jailing in any appreciable or reportable way. The present
invention is directed toward solving this stent jailing problem
through a novel stent and novel method of use.
SUMMARY OF THE INVENTION
[0009] The present invention relates to a novel stent and novel
method of use for treating a bifurcated lesion in a vessel. In one
embodiment, a stent in accordance with the present invention
comprises a lattice defining a substantially cylindrical
configuration having a proximal end portion and a distal end
portion, and a middle portion between the proximal end portion and
the distal end portion. The lattice is movable from a crimped state
to an expanded state. The lattice also has a plurality of adjacent
hoops wherein each hoop has a plurality of adjacent loops. A
plurality of bridges connect adjacent hoops. Additionally, a
plurality of extensions are located on at least some portions of
the lattice. Each of the hoops and extensions define a cell. And,
the proximal end portion and the distal end portion of the lattice
have at least one cell respectively and the middle portion of the
lattice has at least one cell containing a plurality of deformable
extensions. The at least one cell of the middle portion has spacing
between adjacent hoops that is greater than the spacing between
adjacent hoops of the proximal end portion and distal end portion
respectively.
[0010] The plurality of extensions are cantilevered projections
from the bridges of the lattice. And, the plurality of extensions
are movably deformable in a direction away from the lattice and
preferably external to the outer diameter of the stent. Preferably,
at least some of the extensions are movably deformable in a
direction away from the bridges. And preferably, at least some of
the extensions are movably deformable in a direction away from the
hoops.
[0011] Preferably, the stent in accordance with the present
invention has one or more of the extensions that comprise a center
arm terminating in a bifurcation. Additionally or optionally, the
one or more of the extensions comprise one or more arms extending
from the bifurcation.
[0012] More preferably, the one or more of the extensions comprise
a first arm and a second arm extending from the bifurcation. In
some embodiments according to the present invention, the first arm
is at a length shorter than the length of the second arm, or vice
versa, i.e. the first arm is at a length longer than the length of
the second arm.
[0013] Moreover, the stent according to the present invention
further comprises a drug on one or more portions of the lattice. In
other embodiments according to the present invention, the stent
further comprises a drug and polymer combination on one or more
portions of the lattice. Particular examples of appropriate drugs
include rapamycin, paclitaxel and a number of other drugs addressed
later in this disclosure.
[0014] Furthermore, the stent according to the present invention is
made of various materials. One material for the stent is a metal
alloy such as stainless steel. Another material for the stent is a
superelastic material which includes a superelastic alloy such as
NiTi. Other materials include Cobalt based Alloys such as
Cobalt-Chrome (L605).
[0015] Another appropriate material for the composition of the
stent is a polymeric material. In some embodiments in accordance
with the present invention, the stent is made of a biodegradable
polymer.
[0016] The present invention also is directed to a novel method for
treating a bifurcated lesion in a vessel. In one embodiment
according to the present invention, a method for treating a
bifurcated vessel wherein the bifurcated vessel has a main vessel
and a side branch vessel extending from the main vessel comprises
the steps of:
[0017] identifying a site in the main vessel;
[0018] placing a stent at the site in the main vessel, the stent
comprising:
[0019] a lattice defining a substantially cylindrical configuration
having a proximal end portion and a distal end portion, and a
middle portion between the proximal end portion and the distal end
portion, the lattice being movable from a crimped state to an
expanded state, the lattice having a plurality of adjacent hoops,
each hoop having a plurality of adjacent loops; a plurality of
bridges connecting adjacent hoops; a plurality of extensions on the
lattice; each of the hoops and bridges defining a cell; and the
proximal end portion and the distal end portion of the lattice
having at least one cell respectively and the middle portion of the
lattice having at least one cell, the at least one cell of the
middle portion having spacing between adjacent hoops that is
greater than the spacing between adjacent hoops of the at least one
cell of proximal end portion and distal end portion respectively,
the lattice containing a plurality of deformable extensions;
[0020] dilating the at least one cell of the middle portion
adjacent the side branch vessel; and
[0021] supporting a surface of the side branch vessel with at least
one of the plurality of the extensions by deformably moving the at
least one of the plurality of extensions away from the lattice and
into contact with the surface of the side branch vessel.
[0022] In one embodiment according to the present invention, the
method further comprises dilating the at least one cell of the
middle portion adjacent the side branch vessel with a balloon. In
another embodiment according to the present invention, the stent is
made of a self-expandable material such as NiTi and the at least
one cell of the middle portion is dilated due to shape memory
aspects of the at least one cell (adjacent hoops and bridges) and
the extensions associated therewith.
[0023] In other embodiments in accordance with the present
invention, the method further comprises dilating the at least one
cell of the middle portion adjacent an ostium of the side branch
vessel. The dilating of the at least one cell of the middle portion
adjacent an ostium of the side branch vessel can be conducted with
a balloon.
[0024] The method according to the present invention further
comprises placing a second stent in the side branch vessel.
Accordingly, the second stent is placed in the side branch vessel
at the ostium, and/or the second stent is placed in the side branch
vessel adjacent the dilated at least one cell of the middle portion
of the first stent, and/or the second stent is placed in the side
branch vessel within the dilated at least one cell of the middle
portion of the first stent.
[0025] Another embodiment in accordance with the present invention
is directed to a method for treating a bifurcated vessel wherein
the bifurcated vessel has a first vessel and a second vessel
extending from the first vessel. The method comprises the steps
of:
[0026] identifying a site in the first vessel;
[0027] placing a stent at the site in the first vessel, the stent
comprising:
[0028] a lattice defining a substantially cylindrical configuration
having a proximal end portion and a distal end portion, and a
middle portion between the proximal end portion and the distal end
portion, the lattice being movable from a crimped state to an
expanded state, the lattice having a plurality of adjacent hoops; a
plurality of bridges connecting adjacent hoops; a plurality of
extensions on the lattice; each of the hoops and bridges defining a
cell; and the proximal end portion and the distal end portion of
the lattice having at least one cell respectively and the middle
portion of the lattice having at least one cell, containing a
plurality of deformable extensions;
[0029] dilating the at least one cell of the middle portion
adjacent the second vessel; and
[0030] supporting a surface of the second vessel with at least one
of the plurality of the extensions by deformably moving the at
least one of the plurality of extensions away from the lattice and
into contact with the surface of the second vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The novel features of the invention are set forth with
particularity in the appended claims. The invention itself,
however, both as to organization and methods of operation, together
with further objects and advantages thereof, may be best understood
by reference to the following description, taken in conjunction
with the accompanying drawings in which:
[0032] FIG. 1A is a perspective view of a prior art stent of a
closed cell design in a crimped state;
[0033] FIG. 1B is a partial side view of a section of the prior art
stent of FIG. 1A in a configuration conducive for a polishing
manufacturing step;
[0034] FIG. 1C is a partial side view of a section of the prior art
stent of FIG. 1A in the crimped state;
[0035] FIG. ID is a partial side view of a section of the prior art
stent of FIG. 1A in an expanded state;
[0036] FIG. 2A is a partial side view of a prior art stent of an
open-cell design in a configuration conducive for a polishing
manufacturing step;
[0037] FIG. 2B is a partial side view of the prior art stent of
FIG. 2A in a crimped state;
[0038] FIG. 2C is a partial side view of the prior art stent of
FIG. 2A in an expanded state;
[0039] FIG. 3A is a side view of a stent as a closed-cell design
having an open area center section and one or more extensions in
accordance with the present invention;
[0040] FIG. 3B is an enlarged partial side view of the stent of
FIG. 3A in accordance with the present invention;
[0041] FIG. 3C is a perspective view of the stent of FIG. 3A in
isolation after undergoing a cell dilation procedure in accordance
with the present invention;
[0042] FIG. 3D is a perspective view of the stent of FIG. 3A in a
main vessel after undergoing a cell dilation procedure in
accordance with the present invention;
[0043] FIG. 3E is a perspective view of the stents of FIG. 3A in
both a main vessel and a branch vessel in accordance with the
present invention.
[0044] FIG. 4A is a partial side view of a stent as an open-cell
design having an open area center section and one or more
extensions in accordance with the present invention;
[0045] FIG. 4B is an enlarged partial side view of the stent of
FIG. 4A in accordance with the present invention;
[0046] FIG. 4C is a perspective view of the stent of FIG. 4A in
isolation after undergoing a cell dilation procedure in accordance
with the present invention;
[0047] FIG. 4D is a perspective view of the stent of FIG. 4A in a
main vessel after undergoing a cell dilation procedure in
accordance with the present invention; and FIG. 4E is a perspective
view of the stents of FIG. 4A in both a main vessel and a branch
vessel in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0048] As known in the art and best illustrated in FIGS. 1A-1D and
2A-2C, a stent 100,100a respectively is an expandable prosthesis
for a body passageway. It should be understood that the terms
"stent" and "prosthesis" are interchangeably used to some extent in
describing the present invention, insofar as the method, apparatus,
and structures of the present invention may be utilized not only in
connection with an expandable intraluminal vascular graft for
expanding partially occluded segments of a blood vessel, duct or
body passageways, such as within an organ, but may so be utilized
for many other purposes as an expandable prosthesis for many other
types of body passageways. For example, expandable prostheses may
also be used for such purposes as: (1) supportive graft placement
within blocked arteries opened by transluminal recanalization, but
which are likely to collapse in the absence of internal support;
(2) similar use following catheter passage through mediastinal and
other veins occluded by inoperable cancers; (3) reinforcement of
catheter created intrahepatic communications between portal and
hepatic veins in patients suffering from portal hypertension; (4)
supportive graft placement of narrowing of the esophagus, the
intestine, the ureters, the uretha, etc.; (5) intraluminally
bypassing a defect such as an aneurysm or blockage within a vessel
or organ; and (6) supportive graft reinforcement of reopened and
previously obstructed bile ducts. Accordingly, use of the term
"prothesis" encompasses the foregoing usages within various types
of body passageways, and the use of the term "intraluminal graft"
encompasses use for expanding the lumen of a body passageway.
Further in this regard, the term "body passageway" encompasses any
lumen or duct within the human body, such as those previously
described, as well as any vein, artery, or blood vessel within the
human vascular system.
[0049] As used herein, the terms "biodegradable", "degradable",
"degradation", "degraded", "bioerodible", "erodible" or "erosion"
are used interchangeably and are defined as the breaking down or
the susceptibility of a material or component to break down or be
broken into products, byproducts, components or subcomponents over
time such as days, weeks, months or years.
[0050] As used herein, the terms "bioabsorbable", "absorbable",
"resorbable" and "bioresorbable" are used interchangeably and are
defined as the biologic elimination of the products of degradation
by metabolism and/or excretion.
[0051] The stent 100 (FIGS. lA-1D) and 100a (FIGS. 2A-2C) comprises
an expandable lattice structure made of any suitable material which
is compatible with the human body and the bodily fluids (not shown)
with which the stent 100 and 100a may come into contact. The
lattice structure is an arrangement of interconnecting elements
made of a material which has the requisite strength and elasticity
characteristics to permit the tubular shaped stent 100 and 100a to
be expanded or moveable from the crimped state shown in FIGS. 1A
and 1C and FIG. 2B respectively to the deployed or expanded state
as shown in FIG. 1D and FIG. 2C respectively and further to permit
the stent 100 and 100a to retain its expanded state at an enlarged
diameter. Suitable materials for the fabrication of the stent 100
and 100a include silver, tantalum, stainless steel, cobalt-based
alloys such as cobalt-chrome (L605), gold, titanium or any suitable
plastic material having the requisite characteristics previously
described.
[0052] The stent 100 and 100a may also comprise a superelastic
alloy such as nickel titanium (NiTi, e. g., Nitinol). For stents
100 and 100a made of superelastic material, the superelastic design
of the stent 100 and 100a make it crush recoverable and thus
suitable as a stent or frame for any number of vascular devices for
different applications.
[0053] The stent 100 and 100a comprises a tubular configuration
formed by a lattice of interconnecting elements defining a
substantially cylindrical configuration and having front and back
open ends 102, 104 and defining a longitudinal axis 103 extending
therebetween (FIG. 1A). The stent 100 (FIGS. 1A-1D) is known and
has a closed-cell 120 (closed cell design) and the stent 100a
(FIGS. 2A-2C) is known and has an open-cell 120a (open cell
design). Characteristics of open and closed cell designs will be
addressed in greater detail later in this disclosure. In its closed
crimped state, the stent 100 and 100a has a first, smaller outer
diameter for insertion into a patient and navigation through the
vessels and, in its expanded (deployed) state, a second, larger
outer diameter for deployment into the target area of a vessel with
the second diameter being greater in size than the first diameter.
The stent 100 and 100a comprises a plurality of adjacent hoops 106
extending between the front and back ends 102, 104. The hoops 106
include a plurality of longitudinally arranged struts 108 and a
plurality of loops 110 connecting adjacent struts 108. Adjacent
struts 108 are connected at opposite ends so as to form any desired
pattern such as a substantially S or Z shape pattern. The plurality
of loops 110 have a substantially semi-circular configuration and
are substantially symmetric about their centers.
[0054] The stent 100 and 100a further comprises a plurality of
flexible links or bridges 114 and 114a respectively. The bridges
114 and 114a connect adjacent hoops 106. The details of the bridges
114 and 114a are more fully described below.
[0055] The term "flexible link" or "bridges" have the same meaning
and can be used interchangeably. There are many types or forms for
the flexible links or bridges 114. For example, the bridges 114 and
114a may be an S-Link (having an S-Shape or being sinusoidal
shape), a J-Link (having a J-Shape), and N-Link (having an
N-shape), M-Link (M-Shaped) or W-Link (W-Shaped), wherein each of
these configurations can also be inverted.
[0056] In general, bridges 114 and 114(a) respectively are used to
connect adjacent hoops 106. Each bridge comprises two ends wherein
one end of the bridge is attached to a first hoop for example 106,
and the other end of the bridge is attached to a second, adjacent
hoop, for example 106, as shown in FIG. 1A. The attachment points
for the bridge can be at any location on the hoops 106, for
instance, connection points at or directly on loops 110 or struts
108. Thus, bridges that connect at every loop 110 of adjacent hoops
106, define a closed-cell as shown in FIGS. 1A-1D. Moreover,
bridges that connect adjacent hoops 106 at only a select number of
loops 110, e.g. a set number of loops 110 without interconnecting
bridges, define an open-cell such as illustrated in FIGS.
2A-2C.
[0057] The above-described geometry distributes strain throughout
the stent 100 and 100a, prevents metal to metal contact where the
stent 100 and 100a is bent, and minimizes the opening between the
features of the stent 100 and 100a; namely, struts 108, loops 110
and bridges 114 114a respectively. The number of and nature of the
design of the struts, loops and bridges are important design
factors when determining the working properties and fatigue life
properties of the stent 100 and 100a. It was previously thought
that in order to improve the rigidity of the stent, struts should
be large, and thus there should be fewer struts 108 per hoop 106.
However, it is now known that stents 100 having smaller struts 108
and more struts 108 per hoop 106 improve the construction of the
stent 100 and provide greater rigidity.
[0058] FIG. 1D and FIG. 2C illustrate the stent 100 and 100a in its
deployed or expanded state. As may be seen from a comparison
between the stent configurations illustrated in FIG. 1C and FIG. 2B
respectively and the stent configuration illustrated in FIG. 1D and
FIG. 2C respectively, the geometry of the stent 100 and 100a
changes quite significantly as it is deployed from its crimped
state to its expanded or deployed state . As the stent undergoes
diametric change, the strut angle and strain levels in the loops
110 and bridges 114 and 114a are affected. Preferably, all of the
stent features will strain in a predictable manner so that the
stent 100 is reliable and uniform in strength. In addition, it is
preferable to minimize the maximum strain experienced by the struts
108, loops 110 and bridges 114 and 114a since Nitinol properties
are more generally limited by strain rather than by stress.
[0059] With respect to stent designs in general, there are regular
connections which refer to bridges 114 and 114a that include
connections to every inflection point around the circumference of a
structural member, i.e. the loops 110 of adjacent hoops 106.
[0060] Additionally, for stents having an open-cell design, e.g.
100a, there are periodic connections for the stent bridges 114a
that include connections to a subset of the inflection points
(loops 110) around the circumference of the structural members
(lattice). With respect to these period connections, the connected
inflection points (loops 110) alternate with unconnected inflection
points (loops 110) in some defined pattern.
[0061] Moreover, in general, bridges can join the adjacent
structural members at different points. For example, in a
"peak-peak" connection, the bridges 114 and 114a join the adjacent
structural members or loops 110 by joining the outer radii formed
by adjacent loops 110. Alternatively, the bridges 114 and 114a can
form "peak-valley" connections wherein the bridges 114 and 114a
join the outer radii of one inflection point (of a structural
member) to the inner radii of the inflection point of an adjacent
structural member. Additionally "valley-valley" connections are
also possible when the inner radii of inflection points of adjacent
structural members are joined.
[0062] Furthermore, the bridges 114 and 114a between adjacent
structural members, i.e. hoops 106, define cell patterns as briefly
mentioned above. For example, bridges 114 may define a
"closed-cell" formed where all of the internal inflection points,
e.g. loops 110 are connected by bridges 114 as shown in FIGS.
1A-1D.
[0063] Furthermore, it is common for bridges 114 to form a
"closed-cell" which is in essence a sequential ring construction
wherein all internal inflection points of the structural members
are connected by bridges 114. The closed-cells permit for plastic
deformation of the stent 100 during bending thereby allowing
adjacent structural members to separate or nest together in order
to more easily accommodate changes in shape of the stent 100. The
primary advantages of a closed-cell stent design is that it
provides optimal scaffolding and a uniform surface regardless of
the degree of bending of the stent. Depending on the specific
features of a closed-cell design, the stent 100 may be less
flexible than a stent with an open-cell design.
[0064] Turning now to the present invention, the same reference
numerals will be used to designate like or similar features for a
stent 100b (FIGS. 3A-3E), and 100c (FIGS. 4A-4E) in accordance with
the present invention as best illustrated in these figures. One
novel stent 100b in accordance with the present invention is a
closed-cell design stent as best illustrated in FIGS. 3A and 3B. By
way of example, the stent 100b has a center section, center
portion, center segment, middle section, middle portion or middle
segment (all used interchangeably herewith) 105 that contains and
utilizes bridges 114b that connect every loop 110 of adjacent hoops
106. By way of example, the bridge 114b is shown as a
sinusoidal-shaped bridge, however, the bridge 114b can comprise any
particular shape or configuration such as the shapes addressed
above.
[0065] Each bridge 114b has a finger or extension 118 integrally
formed therewith and contiguous with the bridge 114b. In accordance
with the present invention, the extension 118 is a finger or
finger-like projection from the bridge 114b. Each bridge 114b can
include more than one extension 118 extending therefrom. For
instance, the sinusoidal-shape bridge 114b includes one or more
apex 116 and a pocket 115, which is a space directly beneath or
underlying the apex 116 as shown. In this example, the extensions
118 are linear projections and extend from pocket 115 of an
adjacent bridge 114b. Extensions 118 and side extensions 119
(described in detail below) are located at any desired location for
the stent 100b such as proximal end sections, segments or portions
102, distal end sections, segments or portions 104 and center
sections, segments or portions 105. Preferably, extensions 118 and
side extensions 119 are located in center section 105 of stent
100b.
[0066] The extensions 118 extend from each pocket 115 of bridge
114b and are designed as cantilevered projections that are
expandable or movably deformable in a direction away from bridge
114b by balloon force or by shape memory or the like during a side
branch access procedure, for instance, treating lesions and
supporting tissue in a vessel bifurcation, vessel trifurcation or a
vessel having more than two side branches as well as treating
lesions and supporting tissue in a bifurcation of a vessel
bifurcation such as treatment and/or supporting of the iliac
arteries or the like. The extension 118 has a center arm
terminating in a bifurcation 140. Each bifurcation 140 further
includes at least one arm, for instance, a first arm 142 and a
second arm 144. The arms 142 and 144 can have different dimensions,
for instance, the first arm 142 is shorter in length than the
second arm 144 or vice versa, i.e. first arm 142 is greater or
longer in length than second arm 144. Alternatively, the extensions
118 project from the apex 116 of the bridge 114b (not shown).
[0067] Additionally, side extensions 119 are located on each pocket
of adjacent loops 110 and project into the cells 120 located in
center or middle section 105 of the stent 100b. For efficiency
purposes, such as ensuring compactness and low profile for crimping
the stent 100b onto its delivery device or catheter, the
bifurcation 140 is shaped to receive and accommodate the apex 116
of an adjacent bridge 114b. Thus, adjacent bridges 114b will have
adjacent extensions 118 that nest with each other when the stent
100b is in the crimped state. The side-by-side alignment of
adjacent extensions 118, of adjacent bridges 114b is facilitated by
the shape of the bridges (in this example a sinusoidal shape
embodiment) whereby at the underside of each apex 116 resides a
bridge pocket 115 of sufficient size and configuration in order to
receive and accommodate the extension (finger) 118. At a minimum,
the apex 116 of one bridge 114b will fit within the arms 142 and
144 of bifurcated 140 of extension 118 of an adjacent bridge 114b
in the crimped state.
[0068] Additionally, the stent 100b has a center or middle portion
or center or middle section 105 (designated by dashed lines) that
has greater spacing (more open spaced area) between adjacent hoops
106 than the spacing (or size of open space areas) at or near the
proximal end section or segment 102 and the distal end section or
segment 104 respectively of the stent 100b. Thus, the cells 120 of
center section or portion 105 have a greater spacing between
adjacent hoops 106, than the spacing of the cells between adjacent
hoops 106 at or near the proximal end section 102 and the distal
end section 104 respectively.
[0069] A major advantage of the open-spaced center section 105 in
one embodiment in accordance with the present invention, is that
after the stent 100b is expanded in a vessel, such as a main or
trunk vessel 200, it may be desirable to conduct a cell dilation
procedure, for example, a side branch access procedure such as
shown in FIGS. 3A-3E. Accordingly, the cell 120 itself is required
to be dilated. Thus, when the cell 120 of the stent 100b is dilated
through a cell dilation procedure, for example, a side branch
access procedure, the cell 120 is dilated, in one embodiment, by
placing a balloon within cell 120 in the center section 105 and
inflating the balloon within the cell 120. As the cell 120 is
dilated, the extensions 118 and 119 are moved in a direction away
from the bridge 114b and loop 110 respectively as shown in FIG. 3C.
Extensions 118 and 119 are designed to deform such that the
extensions 118 and 119 come into supporting contact with the tissue
of a vessel side branch 220 upon dilation of the cell 120 as shown
in FIG. 3D. This deformation causes an enlarged surface area for
supporting the vessel side branch because the extension 1118, due
to its bifurcated 140 and side arms 142 and 144, facilitates good
contact and supporting surface for the vessel side branch. The
extension 119 also provides additional contact and supporting
surface area for the vessel side branch upon dilation of the cell
120. These same advantages are afforded to the open-cell design
stent 100c (FIGS. 4A-4E) in accordance with the present invention.
Moreover, in another embodiment according to the present invention,
the stent 100b and 100c (FIGS. 3A-3E) and (FIGS, 4A-4E)
respectively are self-expanding stents made of a shape memory
material such as NiTi and the cell 120 (FIGS. 3C-3E) and the cell
120a (FIGS. 4C-4E, addressed in greater detail below) are dilated
by the shape memory aspect of the lattice features defining the
cell, i.e. no separate balloon dilation step is required, but
rather, the cell 120 and 120a respectively is dilated based on
shape memory properties alone, to include deformation of the
extensions 118 and 119 away from the lattice at the cell 120 and
120a respectively.
[0070] Additionally, the extensions 118 and 119 can be located on
any of the loops 110, and struts 108 as well as the bridges 114b or
in any combination thereof.
[0071] In accordance with the present invention, the stent 100b
(FIGS. 3A-3E), and stent 100c (FIGS. 4A-4E), have extensions 118
and 119 respectively located on one or more of the following
components of the center section 105 of the stent lattice in one
embodiment of the invention: the bridges 114b, the hoops 106, the
loops 110, and/or the struts 108. Additionally, in another
embodiment of the invention, extensions 118 and 119 are located on
one or more of these stent features of the proximal end section
102, the center section 105 and the distal end section 104 in any
combination, i.e. extensions 118 and 119 located on the entire
length of the stent or located on one or more of the sections 102,
104 and 105. Moreover, the components of the stent lattice and the
extensions 118 and 119 respectively have drug coatings or drug and
polymer coating combinations that are used to deliver the drug,
i.e. therapeutic and/or pharmaceutical agents including:
[0072] antiproliferative/antimitotic agents including natural
products such as vinca alkaloids (i.e. vinblastine, vincristine,
and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e.
etoposide, teniposide), antibiotics (dactinomycin (actinomycin D)
daunorubicin, doxorubicin and idarubicin), anthracyclines,
mitoxantrone, bleomycins, plicamycin (mithramycin) and mitomycin,
enzymes (L-asparaginase which systemically metabolizes L-asparagine
and deprives cells which do not have the capacity to synthesize
their own asparagine); antiplatelet agents such as
G(GP)II.sub.bIII.sub.a inhibitors and vitronectin receptor
antagonists;
[0073] antiproliferative/antimitotic alkylating agents such as
nitrogen mustards (mechlorethamine, cyclophosphamide and analogs,
melphalan, chlorambucil), ethylenimines and methylmelamines
(hexametbylmelamine and thiotepa), alkyl sulfonates-busulfan,
nirtosoureas (carmustine (BCNU) and analogs, streptozocin),
trazenes - dacarbazinine (DTIC); antiproliferative/antimitotic
antimetabolites such as folic acid analogs (methotrexate),
pyrimidine analogs (fluorouracil, floxuridine, and cytarabine),
purine analogs and related inhibitors (mercaptopurine, thioguanine,
pentostatin and 2-chlorodeoxyadenosine {cladribine}); platinum
coordination complexes (cisplatin, carboplatin), procarbazine,
hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen);
anticoagulants (heparin, synthetic heparin salts and other
inhibitors of thrombin); fibrinolytic agents (such as tissue
plasminogen activator, streptokinase and urokinase), aspirin,
dipyridamole, ticlopidine, clopidogrel, abciximab; antimigratory;
antisecretory (breveldin);
[0074] antiinflammatory: such as adrenocortical steroids (cortisol,
cortisone, fludrocortisone, prednisone, prednisolone,
6.alpha.-methylprednisolone, triamcinolone, betamethasone, and
dexamethasone), non-steroidal agents (salicylic acid derivatives
i.e. aspirin; para-aminophenol derivatives i.e. acetominophen;
indole and indene acetic acids (indomethacin, sulindac, and
etodalac), heteroaryl acetic acids (tolmetin, diclofenac, and
ketorolac), arylpropionic acids (ibuprofen and derivatives),
anthranilic acids (mefenamic acid, and meclofenamic acid), enolic
acids (piroxicam, tenoxicam, phenylbutazone, and
oxyphenthatrazone), nabumetone, gold compounds (auranofin,
aurothioglucose, gold sodium thiomalate); immunosuppressives:
(cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin),
azathioprine, mycophenolate mofetil); angiogenic agents: vascular
endothelial growth factor (VEGF), fibroblast growth factor (FGF)
platelet derived growth factor (PDGF), erythropoetin,; angiotensin
receptor blocker; nitric oxide donors; anti-sense oligionucleotides
and combinations thereof; cell cycle inhibitors, mTOR inhibitors,
and growth factor signal transduction kinase inhibitors. It is
important to note that one or more of the lattice components (e.g.
hoops, loops, struts, bridges and extensions) are coated with one
or more of the drug coatings or drug and polymer coating
combinations.
[0075] Additionally, stent 100b and 100c in accordance with the
present invention are made of any material such as metal alloys,
nickel titanium alloys such as NiTi, including deformable metal
alloys or plastics, metal alloys or plastics that exhibit crushing
or recoil upon deployment of the stent or polymer materials such as
biodegradable polymers and/or bioabsorbable polymers. Thus, the
entire stent 100b and 100c itself (all components) or selectable
components of the stent 100b and 100c in accordance with the
present invention can be made of any of these type of materials to
include plastics or polymers to include biodegradable polymers
and/or bioabsorbable polymers. Additionally, the biodegradable
polymers and/or bioabsorbable polymers used as material for stent
100b and 100c can be drug eluting polymers capable of eluting a
therapeutic and/or pharmaceutical agents according to any desired
release profile.
[0076] As illustrated in FIGS. 3A-3E and 4A-4E, the extensions 118
and 119 are cantilevered projections and terminate in a free end
(not connected to the stent lattice, e.g. connected at only one end
to the stent lattice) that are movably deformable away from the
stent lattice and longitudinal axis of stent 100b and 100c when the
stent is deployed to its expanded or deployed state. In accordance
with the present invention, the extension 118 and 119 can comprise
a different material from the remainder of the components used for
the stent lattice (for instance the hoops, loops, struts and
bridges) especially if a different stiffness is desired.
[0077] As shown in FIGS. 4A and 4B, the stent 100c in accordance
with the present invention is an open-cell design stent also having
a center section 105. The center section 105 has a plurality of
cells 120a having extensions 118 (connected to bridges 114b) and
side extensions 119 connected at the inner most portion of the
loops 110 (for example at the apex of loop 110). Accordingly, the
cells 120a of the center section 105 of stent 100c have a larger
open-spaced area (defined as the spacing between adjacent hoops
106) when compared to the open spaced areas associated with cells
at or near proximal end section 102 and distal end section 104
respectively.
[0078] The same features and functionality as described above for
the stent 100b also apply to the stent 100c in accordance with the
present invention with the exception that the stent 100c is of an
open-cell design.
[0079] As mentioned above, the extensions 118 and 119 enhance the
overall surface area of the stent 100b and 100c respectively
especially when the cell 120 is dilated as part of a cell dilation
procedure for establishing vessel side branch access. The increased
surface area within the space or area defined by the stent lattice
including the extensions 118 and 119, provides not only a
significant advantage in preventing the prolapse of plaque or
tissue into the cell 120a and ultimately into the lumen of the
stent (100b and 100c) when deployed within a vessel 200, i.e. at
the site of a lesion within the vessel, but also provides support
for the tissue of the vessel branch 220 thereby preventing
"jailing" and maintaining good open patency of the vessel side
branch 220. Accordingly, the extensions or fingers 118 and 119
respectively in accordance with the present invention inhibit this
prolapse phenomena thereby providing a prevention barrier against
restenosis of the vessel 200 at the lesion site as well as permit
good blood flow through the vessel side branch 220. Additionally
the extensions or fingers 118 and 119 are good for localized drug
delivery to a very common site for restenosis in bifurcations,
namely the vessel carina and/or ostium.
[0080] In accordance with the present invention, the extensions or
fingers 118 and 119 respectively may also take the form of other
shapes and patterns.
[0081] Additionally, the stent 100b and 100c in accordance with the
present invention may be made from various materials such as those
referred to above. For example, the stent 100b and 100c is made of
an alloy such as stainless steel. Moreover, the stent 100b and 100c
is alternatively made of a crush-recoverable material such as a
superelastic material or superelastic alloy or combination of
alloys. In particular, the stent 100b and 100c is made of nickel
titanium (NiTi) or nickel titanium tertiary alloys thereby
providing it with superelastic and crush recoverable properties as
a self-expanding stent. Preferable materials include those which
are plastically deformable like stainless steel and
cobalt-chrome.
[0082] As mentioned previously, a major advantage of the extensions
118 and 119 respectively, is that the extensions provide enhanced
and/or additional coverage and support at the ostium and carina of
a vessel side branch 220 (FIGS. 3D and 4D respectively) with either
a closed-cell or the open-cell stent 100b and 100c respectively
when the stent 100b and 100c undergo a dilation of the cell 120a as
part of a vessel side-branch access procedure such as the one
briefly described above. Thus, upon dilation of a cell 120a, for
example in the center section 105 of stent 100b and 100c
respectively, the extensions 118 and 119 respectively are cleared
from flow passage at the vessel side branch 220 due to balloon
expansion (in one embodiment of the invention or by shape memory
deformation in another embodiment of the invention), and the
cantilevered extensions 118 and 119 respectively are moved away
from the lattice and cell 120a into a support position (by the
balloon expansion or by shape memory deformation respectively)
against the tissue of the vessel side branch 220 for directly
supporting the side branch vessel 220 thereby forming a stable
graft at the main vessel 220 and side branch vessel 220 junction as
illustrated in FIGS. 3D and 4D respectively.
[0083] Method for Accommodating Vessel Side Branches
[0084] As best illustrated in FIGS. 3D and 3E and FIGS. 4D and 4E
respectively, the novel method for accommodating vessel side
branches and avoiding stent jailing problems in accordance with the
present invention comprises identifying a vessel 200 to be treated
with a stent, for instance by using stent 100b and 100c and placing
the stent 100b and 100c at a site within the target vessel 200. By
way of example, the target vessel can be either a main vessel or
trunk vessel 200 of any artery or one of the minor side branches
220 extended therefrom.
[0085] Additionally, a determination is made as to whether or not
any connecting vessels adjacent the site in the targeted vessel
also require stent placement. This determination can be made either
with prior to placement of the stent 100b and 100c in the target
vessel or after placement of the stent 100b and 100c at the site.
Placement of a second stent 100b and 100c in one of the side branch
vessels 220 or vessels 220 connecting the target vessel 200 after
placement of a first stent 100b and 100c in the main or trunk
vessel 200 or the initial or first vessel 200 is made for purposes
such as treating disease such as stenosis, vulnerable plaque,
ischemic heart disease or the like or for establishing or
re-establishing patency of a side branch vessel 220 or second
vessel 220 by removing obstructions at the ostia of the side branch
vessel or second vessel which may be caused one of the elements or
features of the lattice of stent 100b and 100c, i.e. a "jailing"
problem or by displaced tissue of any one of the vessels such as
intima at the ostia of the side branch vessel 220 or second vessel
220.
[0086] Preferably, when placing stent 100b and 100c in the main
vessel 200 or trunk vessel 200 (the initial vessel or first vessel
to be stented) the center section 105 of the stent 100b and 100c is
aligned at, near or over the ostium of the side branch vessel 220
or second vessel 220 interconnecting the main vessel or first
vessel 200.
[0087] Accordingly, after placement of the first stent 100b and
100c, within the main vessel or first vessel 200 and alignment of a
cell 120 and 120a within center section 105 at, near or over the
ostium of the side branch vessel or second vessel 220, the cell 120
and 120a is identified and expanded, for example, by inserting a
catheter having an expansion device such as a balloon and inflating
the balloon such that the cell 120 and 120a is expanded or dilated
to a larger size (when compared to the size of cell 120 and 120a
after initial placement and prior to dilation of the cell 120 and
120a, i.e. an initial smaller size), or in an alternative
embodiment according to the present invention, the lattice portions
defining the cell 120 and 120a, i.e. the adjacent hoops 106 and
bridges 114b, are expanded as part ofthe self-expanding material of
the stent 100b and 100c to include self-expansion of the extensions
118 and 119 upon deployment of stent 100b and 100c to its expanded
state or expanded configuration.
[0088] Dilation of cell 120a at the ostium of the side branch
vessel or second vessel 220 is accomplished by exerting force upon
the one or more of the components of the lattice defining cell 120a
for the stent 100b and 100c such as the hoops 106, the loops 110,
the struts 108, the bridges 114b, the extensions 118 and 119, the
bifurcations 140, and the arms 142 and 144. Accordingly, an
expansion device, such as a catheter having an inflatable balloon
is inserted into the cell 120a such as being inserted at a location
adjacent or near one or more of lattice components such as those
described above. Inflation of the balloon exerts the requisite
force on the one or more cell defining components of the
lattice.
[0089] Moreover, upon dilation of cell 120a, for example, through
balloon dilation, the components of the lattice are moved away from
the cell 120a as shown in FIGS. 3C and 3D and FIGS. 4C and 4D
respectively. Particularly, the cantilevered extensions 118 and 119
are moved away from the bridge 114b and loop 110 respectively
(moved away from longitudinal axis of stent 100b and 100c). The
extensions 118 and 119 are designed such that portions of the
surface area of the extension 118 (such as the center arm, the
bifurcation 140 and arms 142 and 144) and extension 119 contact and
support the vessel wall of the side branch vessel or second vessel
220, particularly at the ostium thereby providing additional
support for the side branch vessel or second vessel 220 and thereby
preventing prolapse of this tissue at the vessel bifurcation and
thereby preventing jailing of the side branch vessel or second
vessel 220.
[0090] As best illustrated in FIGS. 3E and 4E respectively, after
dilating cell 120a, a second stent 100b and 100c in accordance with
the present invention, is placed, in the side branch vessel or
second vessel 220, i.e. at the ostium of the side branch vessel or
second vessel 220. The second stent 100b and 100c is placed either
simultaneously with dilation of the cell 120a by deployment of the
second stent 100b and 100c upon inflation of the balloon or after
dilation of the cell 120a through use of a second delivery device,
such a catheter, carrying the second stent 100b and 100c.
[0091] While preferred embodiments of the present invention have
been shown and described herein, it will be obvious to those
skilled in the art that such embodiments are provided by way of
example only. Numerous variations, changes, and substitutions will
now occur to those skilled in the art without departing from the
invention. Accordingly, it is intended that the invention be
limited only by the spirit and scope of the appended claims.
* * * * *